Extrusion-molding method



Aug. 22, 1944. c. c. MISFELDT v EXTRUSIQN MOLDING METHOD Filed Aug. 11, 1941 6 Sheets-Sheet 1 INVENTOR. CHARLES C. MSFELDT BY 6964M?! ATTORNEYS Aug. 22, 1944. c. c. MISFELDT EXTRUSION MOLDING METHOD 6 Sheets-Sheet 3 Filed Aug. 11, 1941 INVENTOR CHARLES C .M/sFaor BY I A T TOENEY.

1944- c. c. MISFELDT 2,356,338

EXTRUSION MOLDING METHOD Filed Aug. 11, 1941 6 Sheets-Sheet 4 loz I l/mo I //2 1 INVEN'I'UK. CHARLES C. M'IsFELOT WQ Q W ATTORNEYS Patented Aug. 22, 1944 UNITED STATES PATENT OFFICE My invention relates to method of making extrusion'moldings of metal which have many of the characteristics of drop forgings and which are formed by extrusion and molding forces applied to plastic metal. The product of the machine will herein be known as "molded-extrusions" as distinguishing from ordinary extrusions, die castings, drop forgings, or similar products.

Two problems are prominent in the production of die castings having high tensile strength. -In die casting, the metal is forced while molten into a mold, through a small gate under pressure, and H is held in the mold under relatively low pressure while the metal solidifies, the gate being so small that the pressure is prevented from reaching the mold by metal freezing at the small gate. Great improvements have taken place in the die casting art, but even today great care must be taken to avoid inclusions or gas pockets and shrinkage in the final castings. Also it is diiilcult to make die castings out of metal so that the final casting will have sufiicient tensile strength for many uses for which such castings might be desired. Furthermore, die castings which solidify from the molten state into the solid state while in the mold, have relatively large grain size, and because of porosity and shrinkage subsequent heat treatment cannot be applied without blisters and warping. Such castings still do not have sufilcient tensile strength for many uses. Diecastings also have large shrinkage factors, both internal and dimensional. and are inclined to grow and warp in use.

Another method of producing an irregular ar-' ticle is by drop forging. The heated metal is placed over a die or between two dies, and then hammered into shape by repeated blows. Such drop forgings have excellent tensile characteristics, but are expensive, as the drop forging procedure does not lend itself readily to high quantity production of the articles, and because there is so much machine work to be done to finish the forged part to accurate dimensions, such a forged article has only arough finish,

The means and method to be described herein produce a product in a manner only generally similar to the manner of producing die castings. This product, however, when removed from the mold has the general characteristics of a drop forging or an extrusion with related tensile strengths, such characteristics having been imparted to the product by the use of a novel method and machine for making the product, as will hereinafter be apparent.

Therefore, among the objects of my invention are: To provide a means and method of producing parts or articles by extruding and moulding material thereby giving them the characteristics of drop forgings and of wrought material;

to provide a means and method of controlling the grain structure of castings; to provide a means and method of producing fine grain pressure molded castings of high tensile strength; to provide a machine for extruding and molding a metal to form a molded extrusion; to provide a molded extrusion which has high tensile and yield strength, and adaptability for uses that cannot be adequately satisfied by die castings or sand castings in the finished or semi-finished condition; to provide a means and method of making a molded article of metal or other material; to provide a means and method of making a pressure forging without repeated blows; to provide a means and method of producing pressure forgings in quantity and with uniformity of grade and to finished dimensions; to provide a process and means for producing extrusions, molded to a combination of contours and shapes; to provide a means and process for producing wrought parts that can be machined without distortion to provide a method of producing molded extrusions and pressure forgings that can be heat treated without warping and blistering; and to provide a means and process for producing pressure molded castings that can be heat treated without warpage.

My invention possesses numerous other objects and features of advantage, some of which, together with the foregoing, will be set forth in the following description of specific apparatus embodying and utilizing my novel method. It is therefore to be understood that my method is applicable to other apparatus, and that I do not limit myself in any way, to the apparatus of the present application as I may adopt various other apparatus embodiments utilizing the method within the scope of the appended claims:

In the drawings:

Fig. 1 is a perspective view of the frame and gross assembly of a machine of my invention capable of producing molded extrusions.

Fig. 2 is a longitudinal section, partly in elevation, of the machine of Fig. 1.

Fig. 3 is a fragmentary horizontal sectional view of part of the machine of Fig; 1 showing the structure of the compound hydrauliccylinders.

Fig. 4 is a diagram showing the hydraulic operating circuit for the machine of Fig. 1.

Fig. 5- is a diagram and face view of the barrel of the machine of Fig. 1 showing the circuit for electrical heating of slugs fed into the machine.

Fig. 6 is a detailed fragmentary view, in horizontal section, of the relationship of the barrel, pressure chamber, and mold of the machine of Figs. 1 and 2.

Figs. 7, 8,and 9 are diagrammatic views showing how the residual metal is removed from the pressure chamber.

Fig. 10 is a diagram taken from a photomicrograph of the slug material.

Fig. 11 is a diagram drawn from a photomicrograph of the finished molding.

Figs. 12 and 13 are sectional views of an alternate form of pressure chamber and cutoff mechanism for making hollow moldings, shown in two positions.

Referring to the figures, and particularly to Figs. 1 and 2 for the gross structure of one form of machine capable of performing my method, a base i of heavy construction supports, at each end of the machine, cylinder blocks 2 and 4. Cylinder blocks 2 and 4 are tied together across the top of the machine by a tie rod 6 passing through a pressure block 6 rising from the base and positioned between the two cylinder blocks 2 and 4.

In cylinder block 2 is positioned a dual hydraulic cylinder l having main piston l i projecting therefrom and directed toward one side of pressure block 6. In cylinder block 4 a similar cylinder ill is provided having a main piston ll projecting therefrom and bearing against a slide block I! sliding in guideways l6 forming a part of base I. An axle i1 is provided bridging the gap between cylinder block 2 and pressure block 6, this axle being placed at one side of the center line of the machine and serving to journal a cylindrical barrel 28 having a plurality of slug bores 2i therein. Pressure block 6 is apertured to line with the axis of the main piston I i for the insertion of a pressure chamber insert, this insert being more fully described later. On the other side of pressure block 6 is positioned a'pair of swinging die holders 22, each die holder being laterally rotatable on tie rod 6. Die holders 22 serve to hold die halves 26 laterally, and die holders 22 have angular faced locking lugs 26 and 21 thereon, which engage complementary shoulders 28 on pressure block 6 and movable and complementary locking lugs "on the front face of sliding block II respectively. These die holders may beheated by coils 28. Lugs 28 and 36 are also heated.

This completes the description of the gross structure as shown in Figs. 1 and 2, and a detailed description of composite hydraulic cylinder l8 only will next be given, it bein understood that composite cylinders in and iii are fundamentally identical. The parts of cylinder ill will hereafter be referred to in prime numbers corresponding to the numbers of the parts of cylinder i8.

In Fig. 3 I have shown in detail composite cylinder III as it is seen in horizontal section. Cylinder block 2 is bored out and the cylinder iii inserted therein and held by bolts 82, this cylinder being provided with an open end bearing 85 accommodating main piston ii. This main piston II is provided with a piston head 81 operating in the head space 88 of cylinder ill. The cylinder head 46 of cylinder Iii is provided with a closed end bearing 4|, this end bearing fitting a hollow axial rod 42 extending entirely through the piston head 81 in piston head bearing 43,

. then into a secondary piston chamber 46 in piston ii, there to be attached to a secondary piston 46. Rod 42 is then continued through the remainder of chamber 46, through main piston end bearing 48 to project outside of piston Ii for purposes as will be hereinafter set forth. The front face 66 of piston II is so machined as to take various extensions as may be desired, and the inner end at rod 42 is provided with threads 6i as shown in Figs. 7, 8, and 9, so that the inner end may be plugged if desired with a proper tip, or may be left open to carry fluids or tubes, as will be explained later.

The main piston is to be controlled hydraulically, hence piston space 88 is provided with a hydraulic control bore 62 at one end thereof and a smaller bore 68 at the other end, for the passage of a hydraulic fluid such as oil into and out of the head space 88 on each side of piston head 21. Secondary piston chamber 46 is provided with a fluid conduit 55 opening on one side of piston 46 and a fluid conduit 66 opening on the other side of piston 46, these conduits running in main piston ii and terminating near the end thereof in connections for flexible pipe. The main piston ll may be progressed hydraulically along cylinder It as desired, carrying with it piston 46 and rod 42. At the same time, however, piston 46 may be controlled as to its position within the main piston Ii by hydraulic pressure. Thus I am able to obtain a diiferential action as between the main piston II and the rod 42 for various purposes, as will be described later.

I will now describe the machine as set up for the making of molded-extrusions, as shown in Figs. 2 and 6, Fig. 6 being an enlargement of the portion of Fig. 3 having to do with the loading and extruding chambers of the device.

As previously described, rotating barrel 26 is provided with a plurality of slug recesses 2 i. Each slug recess is bored in a slug recess insert 66, each insert being electrically heated by heating coils 6i. Each insert is also provided with a long brush 62 and a short brush 68, these brushes forming the termini of the related heating coil 6i. The brushes extend outwardly and as the barrel 20 is rotated, the short brush contacts a short brush segment 65, and the long brushes contact, in order, outer segments 66, 81, and 68, as the barrel is rotated clockwise as seen in Fig. 5. By changing the energization of segments 66, 61, and 68 from a power source 66, by the use of resistors 16, the temperature of the slugs when placed in the slug chambers can be accurately controlled during feeding of the slugs. Each insert 68 is provided with a coned end 1i engaging a complementary surface on a pressure insert I2 mounted in pressure blocks 6. This pressure insert I2 is provided with a pressure chamber 18 of the size of the slug chambers 2|, and the chambers are coextensive when registered. Pressure insert 12 is also heated by pressure insert heating coil 16.

Slugs are transferred from a slug recess 2| to the pressure recess 13 by extension 16 attached to the outer end 56 of piston ii, this attachment being hollow for the passage of rod 42, and provided also with a restricted aperture 11 on the end thereof, through which a plug projection 18 may pass, this plug projection being screwed in the end of rod 42. The outlet end of pressure chamber I3 is provided with a throat 80 of generally Venturi shape, the small end of throat I. registering, under normal conditions, with cutoff apertures in cutofl' plates 88 and 86, these apertures normally being alined with the small end of throat 86, one of these cutoif plates 86 assasaa being vertically movable by a hydraulic cylinder system as shown in Fig. 2. Plate ll may be moved downwardly so that aperture 02 will reglater with a knockout piston 81 operating in knockout cylinder 08 hydraulically controlled. Die plates 25 are made to have an inlet opening 00 registering with the apertures in the cutoff plates so that metal passing through throat 80 will flow into die space 9 I Referring now to Fig. 4 for a description of the hydraulic control for my device. In this figure which is diagrammatic only the auxiliary pistons 46 and 40'. have been shown as separated from the main pistons II and II' for clarity of illustration. A main tank I00 is provided with a main pump A, pumping hydraulic fluid such as oil into an accumulator cylinder IOI. The accumulator cylinder carries an accumulator Diston I02 which, when moved upwardly by oil in cylinder IOI, moves a weight I03 upwardly and thus oil under pressure is accumulated in cylinder IOI. Cylinder IOI discharges into a main line I 08 which is divided into a main pressure line I06 for the cylinder I0 entering through bore 52, and a backup line I01 for protecting valve I08 used to control cylinder I0. Pressure line I 06 is under the control of a main valve H0 and a main sump line III leads from valve IIO back to main tank I00.

Inasmuch as I may not desireto utilize the high pressure fluid for preliminary movements of the pistons, I provide an auxiliary control system comprising pump B pumping fluid from an auxiliary tank II 2 through control lines H5, H6, and III.

Pressure from line III is led through valve III to bore 53 in cylinder I0, and also through protected valve I08 to either side of piston I I, as desired. Thus piston II may have accumulator pressure on one side thereof and control pressure from pump B on the other side, whereas piston II' uses only pump B pressure for movement thereof. However, piston II may be controlled by the accumulator if desirable.

The auxiliary pistons 46 and 46' are controlled by auxiliary valves H8 and II!) respectively under pressure connected to lines H and Hi. All valves have sump returns so that when one side of the pistons is placed under pressure the other side will drain into the sump.

The head end of cylinder I0, which is subject to the direct pressure from accumulator cylinder IN, is provided with a relief valve I so that the pressure applied to piston II can be regulated for extrusion of different materials without changing the constants of the accumulator. Line III also supplies cutoff cylinder 86 and knockout cylinder 81 under the valve control.

It will be obvious from the brief description given of the hydraulic system that many of the control valves may, if desired, be interlinked and operated manually or automatically to follow a predetermined cycle.

Having thus described how the pistons may be operated I will now proceed to describe the operation of the machine as set up for making a simple molded-extrusion without a central aperture. In this case the die blocks are placed.

together after a molded-extrusion has been discharged, and enclosed by die holders 22. 'In order that these die holders be free to discharge the previous forging, sliding block I5 has been retracted by operation of main piston II, and the die holders 22 have been moved along tie rod 5 to free locking lugs 20 and 21 from shoulders 20 and 30. After the die is closed and the die holders closed thereon, sliding block II is then moved toward pressure block 8 by the use of valve I00 until the die holders 22 are firmly locked in position, with the opening of the die adjacent to the openings in cutoiI plates BI and 02. The latter have been moved to register by the use of hydraulic cylinder 06 which is also operated from auxiliary pump B. Valve I 00 is closed, thus providing a hydraulic lock for piston II'. The slug recesses are loaded and the barrel is rotated with the slugs in recesses 2| being heated electrically as the barrel is rotated with a final and high heat just prior to the rotation of the brushes oil. of segments 65 and 68, so the the preheated slug may then be brought into registry with pressure chamber I3. At this time the main piston II is operated by use of valve IIO to force the preheated slug out of the slug recess 00, heat is developed at this point. This additional heat is sufiicient to reduce the end of the slugin the throat to a mushy or plastic condition so that the metal will flow in a mushy, thick condition through the registering openings into the die cavity. The shape of the throat 00 may be so regulated and designed that the heat developed at that point will never be sufiicient to bring the metal into atrue molten condition, but only enough to maintain the metal suillciently plastic to pass through the openings into the die cavities and under suillcient pressure to be in solid solution. A variation in the ratio between the orifice and the piston diameter will regulate the grain size and temperature of the mushy material extruded into the cavity of the mold, to be upset therein.

As the main piston II through extension I6 is forcing the mushy slug material into the die cavity the accumulator weight I03 is, of course, falling and exerting high pressure on the face of extension 16. As can be seen in Fig. 7, the interior piston 48 may be operated during the progression of the main piston to bring tip I3 mounted on rod 42 flush with the face of piston extension 10 so that as the extension I0 moves to force the slug out of the pressure chamber, the extension has in efiect a flat face presented to the slug. However, just as the extension I0 reaches its final position, registering with the beginning of throat 80 as shown in Fig. 8, rod 42 may be retracted so that a portion of the slug metal (plastic at this point) enters the hollow end of extension I6 to form a residual metal stem 200 which will remain attached to residual metal 20I which will remain in throat 80.

However, as the main piston travels forward and reaches the end of its stroke, the die cavity 9| will become full. Consequently no more mushy metal may be forced through throat 00 into the die cavity. Accumulator weight I03 has of course been falling during the progression of the slug metal through the throat 00', and as the die cavity becomes full, the energy of weight I03 is expended on the metal in the die, with a final high pressure as may be regulated by weight I 03, by the relative sizes of the various pistons, by the distance through which weight I03 falls, or-by any setting of relief valve I20. At the same time the die blocks 25 are being heated by electrical coils 23 in the die holders, so that the metal in the die blocks, after extrusion and at the time of the application of the extreme high pressure from adcumulator I03, can be held at any temperature desired. I prefer to control this temperature so that Just as the metal is about to solidify in the die cavity the high pressure be applied. The sudden application of the extremely high pressure from the accumulator, together with the working of the metal in the throat 80, completely changes the character of the extruded material, and make-v the grain structure much more comparable to a forging than to a casting, as will be explained more in detail later.

It will be noted that while the high pressure is applied only by piston l I, this pressure, through the die blocks, is also applied to sliding block I! and piston II. This piston being under a hydraulic lock by closure of valve I08, piston Ii therefore exerts a high pressure on valve I08, and to safeguard this valve, I apply through line I01 the pressure of the accumulator to prevent valve breakdown and to balance the valve elements during the application of high pressure thereto.

As the metal in the die cavity 0| is chilling, and

The grain is then further worked by the impact pressure and the end result is a fine grained article.

Because the mushy material going into themold is solid and viscous it expels the air in the mold very much like a piston pushes oil out of a cylinder. Porosity cannot occur under these conditions. The metal is not broken up or sprayed, as it might be if liquid were to be forced in quickly. The air is therefore pushed out of the mold without mixing with the incoming metal in any manner.

I have found, for example, using slugs of beryllium copper, that by using a 5 second extrusion time with 60,000 pounds extrusion pressure and a final forging pressure of from 200,000 to 225,000 pounds per square inch, molded-extrusions can be made which have many of the desirable characteristics of drop forgings, and which are in no way comparable to die castings made of the same material in the usual manner, but which compare in physical properties to the same metal extruded in continuous pieces by the cold extrusion method common to the industry.

The process as thus described, and the product which is produced, difler radically from die casting, although it will be obvious by inspection of while the throat metal is still plastic, plate 82 is moved downwardly by action of hydraulic cylinder 86, thus cutting the metal between the die cavity and the throat 80 and bringing the cutout portion in aperture 82 opposite piston 81 which may then be operated toknock out the separated portion. This cutoff frees the metal in the die cavity ill from the residual metal 200 and 2M left in the pressure cavity. Pressure may then be released from both cylinders and the piston I' may then be operated to retract sliding block is to allow the completed chilled molded-extru- $1011, or forging, to be taken out of the die cavity. At the same time the piston II is retracted carrying with it the residual metal 200 and 2M as shown in Fig. 9. The portion 200 has, of course, been molded into threaded engagement with the threaded end of piston extension 16 and this threaded engagement is sufilcient to break loose the portion 2M from its throat engagement as the extension is retracted. After the piston extension l6 has been retracted sufficiently to bring the portions 200 and 2M out into the open on the cylinder i0 side of barrel 20, the portions 200 and 20! are unscrewed from the end of the piston extension. However, each slug may hold enough metal to make many parts. Also, some metals permit the re-use of residual metal by leaving it in the chambers and extruding it on the next cycle through the orifice into the mold. Thus a perfect homogeneous joint is the result.

When the slug metal is used up, barrel 20 is then indexed to bring the next pre-heated slug again into registry, the die reassembled, placed in position, and the cycle repeated.

When the extruded, refined and mushy plastic material moves from the reducing orifice into the cavity of the mold, it moves to the opposite end of the cavity and is upset there. In other words, the metal actually changes shape at the far end of the mold and is formed until its diameter and shape is telescoped to fit the exact shape of the cavity. This change in shape is important because it provides a definite further working of the metal inside of the cavity during filling thereof, this working taking place while the temperature is being reduced by chilling of the metal.

the machine that pressure-mold casting from molten or mushy metal can be accomplished when temperatures and pressure are adjusted for such castings, and even in this case a final forging pressure greatly improves the casting. The machine will handle materials which do not die cast readily, but which can be pre-heated and thereafter extruded in plastic mushy form into the die to a desired shape in a single operation.

' The change in the grain structure is diagrammatically represented in Figs. 10 and 11. Fig. 10 is taken from a photomicrograph of the cast slug material before it has been passed through the machine, and Fig. 11 is a representation of the same material as it appears under the microscope after having been fabricated into a moldedextrusion after the method just above described. It can readily be seen that the grain structure has completely changed and that the grain of the final product is extremely fine and uniform, giving characteristics to the product which is much more like a drop forging or cold extrusion than like a casting.

The increase in the temperature caused by the working due to increasing pressure in the throat, does not cause oxides and has a tendency towards closer wedding of grain structure while the metal is being reduced in diameter by extrusion.

Barrel 20, which holds the metal slugs before they are passed into the machine may, of course, be automatically indexed. During the regular cycle of operation of the machine, this barrel will preheat each sing to exactly the same temperature. The function of the preheating cycle,

however,'is not merely the preparation of the slug material for presentation to the pressure chamber 13 in order that the time of stay in pressure chamber 13 may be reduced. It is also for the purpose of giving the slugs a heat treatment which may, if desired, be of even higher temperature than the temperature of the slug when it is being forced through the pressure chamber- The preheating of the slugs therefore is important in determining the type of grain structure which is attained in the final forging. The complete cycle therefore includes preheating of the sings to definite temperatures in ac- .The temperature of the cordance with the type of alloy or metal being extruded, a conversion into a fiowable mushy plastic because of extreme high pressure, and a final chilling in the die cavity, this latter change of temperature serving as a quench. Inasmuch as themetal before quenching is plactic, accurate control of the proper temperatures can be obtained by pressure regulation, without the use of thermometers. The proper quenching temperatures can be established by adjustment for any of the alloys used in the preheating stage, and by changing the shape and size of the throat 80 to give the required plasticizing temperature. mold can be controlled and changed as desired by heating and cooling of the mold parts.

It should also be noted that the working and compressing of the metal in the mold before chilling or quenching completely eliminates warping of the final forging. The high pressure applied to the metal inthe die works the metal right up to the point of freezing. This eliminates the need for shrinkage allowances in machining the cavity in the die. The metal is always under enough pressure while it is chilling to overcome this very usual fault of the common die-casting procedures. Thus, my method and machine permit very accurate parts to be molded to the very closest tolerances. The treatment is also extremely uniform because the operation of the machine can be made wholly automatic in opera-. tion, and be made to operate under a regular Furthermore, parts made by my process, as described herein, may be heat-treated without substantial distortion.

In Figs. 12 and 131s shown diagrammatically a modification of my invention for use in making hollow forgings. In this case hollow rod 42 of piston II is projected through the sliding block l5, through the die block and the die space 9| to form a core or mandrel therein. In this respect it will be noted that the die and mandrel arrangement so set up is ideally adapted for the production of tubing or, by using a die properly cut, for the production of rifle barrels, for example. In this case .a hollow slug is through the center of the slug and has an end recess 2 therein registering with the end of hollow tube 42' of piston I l As no cutoif plates "or 85 are used, and while the metal is still in plastic condition, rod 42 is progressed toward the small end of the throat to pinch oif the metal, leaving the die metal completely free from the residual metal 2lll in the throat 80. Inasmuch as the end of tip m is larger than the diameter of rod 42, the throat metal will be retracted with the retraction of the thus freeing the forging and providin a means for removing the throat may then be unscrewed from rod metal 20l removed.

end of rod 42' rial retracted, the mandrel rod 42' so that it may be rapidly cooled or quenched after the final impact and setting has taken place.

The device, therefore, as just described may be utilized for making long tubular materials and is, as stated above, ideally satisfactory for the production of rifle barrels, together with all exterior conformations thereof, all in one piece. I hav found that beryllium-copper rifle barrels may be formed in this manner, which require very little finishing, and that the bore thereof, as produced by the mandrel rod 42, is sufllciently accurate to need only a final sizing and rifiing with a breach.

After the tubular forging has been separated from the throat material and the troat mate- 'ay then be retracted through the die by applying pressure to piston 46', the piston I i retracted, and the forging can be removed.

In case a tubular core is to be left in the tubularmolding I then prefer to utilize cutoil' plates 84 and 85, to remove plug 11 from rod 42 and run the tubular core through the interior of red", through the die and then into rod 42'.

This core then remains in article, the tube being cut oil by the shearing action of plates 84 and 85. For each new extrusion the core may be fed into the die through rod 42, either automatically or by hand.

place in the molded The same machine with various temperature adjustments can accommodate all of the various results therein described on various types of gun or ordnance parts, such as gun barrels, brackets, bolts, etc.,a'nd also all manner of fittings for machines, automobiles, airplanes, boats of any description, as well as small apparatus or tools,

be reduced in cost This machine, while it is described as hand controlled in operation, can be as easily made full or semi-automatic, and still accomplish the complete cycle of operation as required to execute the fabrication of the part as tooled.

My machine can handle pig material, cast or wrought bar, or pressed powder, or can be adapted for either pressed, molded, or cast blanks. It can also use cutout pieces of metal or material that has suitable specifications to permit the properoperation of the machine. When materials to be pressure-forged are molten, pressures can be reduced as compared with those required for extruding and molding plastic material. My machine and method is practical for all materials that are converted to a plastic up .to 2000 F.

I claim:

1. The method of making a molded-extrusion which comprises heating said metal to a point constricted orifice, and directing said mushy plastic metal immediately into a mold.

2. The method of making a molded-extrusion which comprises heating said metal to a point just below a mushy plastic state thereof, additionally heating said metal to a refined mushy plastic stage by forcing said metal through a constricted orifice, directing said mushy plastic metal immediately into a mold, and suddenly applying an additional pressure to the metal in the mold as freezing occurs.

3. Method in accordance with claim 2 wherein said first pressure is on the order of 50,000 pounds per square inch on the order of 200,000 pounds per square inch.

and sald'additional pressure is 4. The method. or making a molded-extrusion whichcomprises converting a solid mass of metal into-mushy plastic condition by the simultaneous action or heat and pressure, forcing the mushy plastic metal immediately into a mold to the point of filling the same, permitting said metal to freeze, and applying a higher pressure to said metal as said metal freezes.

5. The method or making a molded-extrusion which comprises converting a solid mass of metal into plastic condition by the simultaneous action of heat and pressure, extruding the plastic metal into a mold to the point of filling the same, permitting said metal to ireezerand applying a higher, single pressure impact at a predetermined pressure to said metal as said metal freezes.

6. The method or plasticizlng and simultaneously working a solid metal slug which comprises progressively extruding said slug through a reducing orifice to raise said metal at said oriilee only to a mushy plastic temperature by applying pressure to the solid portion of said slug. and directing the extruded refined mushy plastic metal immediately into a mold.

CHARLES C. MISI 'HDI. 

